Mobile scaffold

ABSTRACT

A mobile scaffold suitable for use in working at elevated positions on the outside or inside structure of buildings, the said scaffold being mounted on a supporting platform with means to automatically move the scaffold to selected elevated positions, the said scaffold working area remaining parallel to the platform area at all times; the said support platform having levelling means and independent motion means to move it from one location to another.

United States Patent Inventor James B. Mahaney 401 E. Downing St., Tahlequah, Okla. 74464 Appl. No. 55,374 Filed July 16, 1970 Patented Sept. 28, 1971 MOBILE SCAFFOLD 6 Claims, 4 Drawing Figs.

US. Cl 182/2, 182/12 Int'. Cl B661 11/04 Field of Search 182/2, 63,

[56] References Cited UNITED STATES PATENTS 2,500,815 3/1950 Gerli 182/2 3,087,581 4/1963 Pitman 182/2 3,176,792 4/1965 Olson 182/2 3,470,980 10/1969 Irwin 182/2 Primary Examiner-Reinaldo P. Machado Attorney-Ralph E. Zimmerman ABSTRACT: A mobile scaffold suitable for use in working at elevated positions on the outside or inside structure of buildings, the said scaffold being mounted on a supporting platform with means to automatically move the scaffold to selected elevated positions, the said scaffold working area remaining parallel to the platform area at all times; the said support platform having levelling means and independent motion means to move it from one location to another.

PATENTEnsEP28m| 3508.668

SHEET 1 UP 3 INVENTOR. JAMES B. MAHA NEY ATTORNEY miminsmsm. 3808.668

SHEET 2- {1F 3 CF/ .2 INVENTOR.

' JAMES B. MAHANEY ATTORNEY .5 INVENTOR. 6 5 JAMES B. MAHANEY mm M A T TOR/v5 Y MOBILE SCAFFOLD BACKGROUND OF THE INVENTION This invention relates primarily to a mobile scaffold particularly to a scaffold which is mounted on a stationary platform or a trailer, the scaffold being supported by articulated members in a pattern to raise the scaffold to selected heights approximately parallel to the stationary platform. The stationary platform is maintained in a selected horizontal position by the adjustment of levelling jacks located at each corner of the platform. A mobile scaffold is shown in the U.S. Pat. No. 2,964,122, to Funk, et al., issued Dec. 13, 1960. This scaffold is manually assembled and then erected to the desired height with ladder means attached to the scaffold. The U.S. Pat. to Olson, No. 3,176,792, issued Apr. 6, 1965 shows a movable work platform with means to move a basket assembly vertically and laterally; however, the operation of this work platform differs from the mobile scaffold, the differences of which shall become apparent from the description of the invention in the following paragraphs.

The main object of this invention is to provide a mobile scaffold assembly that can be raised or lowered at will and yet have the scaffold working area remain level and parallel to the support platform.

Another object of this invention is to provide means which will move at will the mobile scaffold in an up and down direction, maintaining the mobile scaffolding approximately parallel with the support platform at all times.

Another object of this invention is to provide safety levelling means for adjusting the level of the support platform when the mo bile scaffold unit is in a working position.

Still another object of this invention is to provide independent mobile apparatus for moving the scaffold to any desirable location.

And still another object of this invention is to maintain the vertical travel of the scaffold in a precise pattern during vertical movement of the scaffold.

FIG. 1 is a perspective drawing showing the mobile scaffold assembly on a support platform.

FIG. 2 is a line drawing showing the rear view of the mobile scaffold assembly on the support platform with a first mechanism for elevating and lowering the scaffold work area.

FIG. 2a is a line drawing partially showing a second mechanism for elevating and lowering the mobile scafiold.

FIG. 3 illustrates the portable means for moving the scaffold platform from one working area to another working area.

Reference is made to FIG. 1 which shows the complete mobile scaffold in operating position with supporting platform 1 and levelling jacks 2. The scaffold assembly itself shown as 4 consists of a safety shield 3 and a shelf 5 at an approximately 90 angle to each other with the shield 3 attached at an approximately 90 angle to the working platform 6. The scaffold assembly per se 4 is suspended between elevating segments 9 and 9', and the elevating structure 7 is further reinforced by a support bar 28. The elevating segments 9 and 9 are similar and are both pivotally attached to the scaffold assembly framing 4 as shown in FIG. 1. The entire elevating structure 7 is attached to platform 1 by fasteners 16 and 16'. The supporting platform shown as 1 is typical of a mounting base necessary to support the elevating structure 7. The elevating structure 7 consists of elevating segments 8, 9, 8 and 9' for the scaffold assembly 4, pulleys l2 and 13, FIG. 2 and 12' and 13, FIG. 2a furnish the means for supporting cables 23, FIG. 2 and 23, FIG. 2a, respectively. Cables 23 and 23' actuates supporting segments 8,8, 9 and 9 through members l0, 11 and 11 into an approximate vertical position, cables 19, 20, 21 and 22, FIG. 2 and a similar set of cables 19', 21' and 22', FIG. 2a maintain the scaffold assembly 4 in an approximately level position with the platform 1. The detailed operation of the pulleys and the cables referred to above will be reserved for the explanation of FIG. 2 and 2a. Reference is made to the supporting platform or trailer 1, FIG. I. The supporting platform 1 is constructed either from light steel plate or the usual 75 ments 8 and 8' angle iron with a wood bed. The angle iron on each of two ends of platform 1 is reinforced with steel reinforcing bars 15 and 15 upon which is mounted fasteners 16 and 16 for support segments 8 and 8' and fasteners 17, 17', 18 and 18' for cables 19, 19', 20 and 20' which are also fastened to reinforcing bars 15 and 15' respectively on one end and on crossbar l4 and 14' on the other end. From crossbar 14 and 14', cables 20, 20', 21 and 21' are extended to scaffold assembly structure 4. The purpose of cables 19, 19', 20, 20, 21, 21', 22 and 22' in combination with crossbar l4 and 14', is to maintain the scaffold working area 6 in level position with the supporting platform 1 at whatever random working height is selected. To level the supporting platform I manually operated jacks shown as 2 and 2, FIG. 2 are positioned at each of four corners, two jacks 2 and 2 each are connected into cross member extensions 25 and 25 located at each of two ends of the supporting platform 1. The levelling jacks 2 and 2 on one side of the supporting platform 1 attached to extensions 25 and 25 to provide for additional levelling space to locate the levelling jacks 2 and 2' in case of uneven ground at the comer positions of the supporting platform 1.

The means for raising the elevating segments 8 and 8 is through elevating screwjacks 24 and 24; elevating segments 9 and 9 are raised by separate means consisting of members 10 and 11, 10 and 11', pivotally mounted on structural segments 8, 9 and 8 and 9', members 10, I1 and 10, ll join in a pivoting point on pulley 12 and 12. Pulley 12 is connected to pulley 13 by a cable 23 which passes from pulley 12, around pulley 26 three times to an electrical winch 30. Pulley 12' likewise is connected to pulley 13' by cable 23 which passes from pulley 12, around pulley 26' to the same winch 30. By retracting the cable 23, pulley 12 is drawn toward pulley 13 causing the elevating segments 10 and 11, pivotally connected to elevating segments 8 and 9, to move to an open position. The screwjack 24 and the movement of the pulley 12 independently operated can be synchronized by the operator so that the upward movement of the elevating segments 8 and 9 will gently move the working platform 6 in a vertical plane and/or a horizontal plane to a selected height. Elevating segments 8 and 9' are likewise, moved upwardly in a manner similar to elevating segments 8 and 9. The up and down movement of the working platform is selectively controlled by workmen on the working platform 6 or by an operator on the ground level. The controls are cabled toggle safety switches 42 and 43, FIG. 1, with means to place the actuating means in a forward, reverse and stop position. Control cable switch 42 controls the electric motor 27 that operates screwjacks 24 and 24, the other control cable switch 43 operates the electric winch 30 which actuates the movement of elevating members 9 and 9.

Reference is made to FIG. 2 which shows the end view of the supporting platform 1 with levelling jacks 2 and 2'. Elevating screwjacks 24 and 24' are shown attached to a drive shaft 29 with a source of power in electric motor 27 connected by a belt drive 30 through a pulley mounted on drive shaft 29. Levelling cables 19 and 20 are shown connected by fasteners 17 and 18 to the reinforcing bar 15 on the supporting platform 1; levelling cables 21 and 22 are shown attached to the working platform structure 4; levelling cables 19 and 20, 21 and 22 are all shown connected to stationary crossbar 14. The purpose of levelling cables 19, 20, 21 and 22 is to maintain scaffold 4 in approximately parallel alignment with platform 1. As scaffold 4 moves in a horizontal and/or vertical direction, levelling cables 19, 20, 21 and 22 maintain the horizontal position of working platform 6 regardless of the position of elevating segments 8 and 9 and/or the duplicate elevating segments 8' and 9', FIG. 1 on the other end of the platform 1. Mounted on platform 1 is electric motor 27 which is connected by a belt drive to a center drive shaft 29. The center drive shaft 29 is centrally connected to both screwjacks 24 and 24, FIG. 1 on each end of the platform 1. The electric motor 27 through its drive shaft 29 furnishes the power to expand the screwjacks 24 and 24 in an upwardly direction, moving the elevating segto a vertical position. The electric motor 27 which actuates the screwjacks 24 and 24' is controlled by a hand-operated cable switch 42, FIG. 1 either on ground level or by an operator on the scaffold. The screwjacks 24 and 24 are pivotally attached to segments 8 and 8' respectively so as to elevate segments 8 and 8 in an upwardly direction. Since segments 8 and 8' are pivotally connected into a common junction with elevating segments 9 and 9' at sheave l3 and 13, segments 9 and 9 move in the same plane. Cables 19, 20, 21 and 22, FIG. 2 and 19, 20, 21' and 22', FIG. 2a are attached to crossbars 14, FIG. 2 and 14', FIG. 2a mounted on sheave 13 and 13' to keep the scaffold assembly 4 approximately parallel to the platform 1 when members 8, 9, 8 and 9 are being elevated. Elevating members 8 and 9 which are structurally similar to elevating members 8 and 9 are moved in sequence with members 8 and 9 by screwjacks 24 pivotally connected to member 8' and actuated by drive shaft 29. Elevating members 8' and 9 operate precisely as the first set of elevating members 8 and 9.

FIG. 2a is a partial view of the second linkage mechanism which is part of the elevating means which is attached to the other side of the scaffold assembly 4. Elevating segments 8' and 9' are shown in common junction at sheave 13', crossbar I4 is shown attached to sheave l3; cables 19', 20, 21' and 22' are shown attached to the outer extremities of crossbar 14'; the four crossbars being in a 90 relationship to each other. Cables 19' and 20' extend from the crossbar 14' extremities to fasteners 17 and 18', FIG. 1 and cables 21' and 22', FIG. 20 extend from the crossbar l4 extremities to the scaffold 4 frame structure at 31 and 32'.

FIG. 3 is a front elevation showing a motor driven single wheel assembly 33 which is used to move the mobile scaffold 1, FIG. 1 short distances from one location to another location. TI-Ie single wheel assembly 33 has a hollow tube 34 assembled on a frame 35. The hollow tube 34 fits over screw rod 36 in a ball bearing collar with a yoke 37 attached to the ball bearing collar 36. Mounted in the yoke 37 is a wheel 38. On top of the hollow tube 34 is a handle 41 which is used to adjust vertically the wheel assembly 33. The wheel assembly 33 is mounted onto the platform 1 by means 44 and is equipped with an electric motor 39 which furnishes power topulley wheel assembly 40. Pulley wheel assembly 40 through pulleys and V-pulley belts transfers power to the wheel 38. Handle 41 is used to adjust the height of the wheel 38 in relationship to the ground level.

OPERATION OF THE MOBILE SCAFFOLD The mobile scaffold is transportable either assembled on a trailer with the levelling jack 2 as portrayed in FIGS. 1 and 2 removed or in the alternative the mobile scaffold can be mounted on a mobile platform which is movable by means as shown in FIG. 3. When the mobile scaffold is on location, the four levelling jacks 2 and 2' are extended as shown in FIGS. I and 2. To raise the scaffold assembly 4 the operator on ground level or on the working area 6, FIG. I of scaffold 4, FIG. I presses a first toggle cable switch 43, FIG. 1 to raise both lower elevating segments 8 and 8' simultaneously in an upwardly direction.

This moves the scaffolding assembly 4 in a forward and upward direction. To keep the scaffolding assembly 4 moving in a vertical direction, the operator must press a second toggle switch. This toggle switch actuates an electric winch 40 with a drum upon which is mounted cables 23 and 23. The electric winch takes up cables 23 and 23 simultaneously. In preferred embodiment the cables 23 and 23' are attached to pulleys I2 and 12' respectively and pass around pulleys l3 and 13' three times and around pulleys 12 and 12' twice. The cables 23 and 23 then pass from pulleys I3 and 13' to pulleys 26 and 26' respectively, then to the drum of electric winch 40, braces and 11, FIG. 1 and braces 10 and II, FIG. 2 move outwardly when pulleys 12 and 12' moves toward pulleys l3 and 23', respectively. The movement of braces 10 and M and 10' and 11 causes segments 9 and 9 respectively to move upwardly.

Since segments 9 and 9 are pivotally attached to scaffold assembly 4, the scaffold assembly 4 moves upwardly. The height and the horizontal movement of the scaffold assembly 4 can be independently regulated by the use of the individual toggle switches 42 and 43, FIG. 1, since segments 8 and 8 are controlled by toggle switch 43 and 9 and 9' are controlled by toggle switch 42.

It will of course be understood that various details of construction may be varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted herein otherwise than necessitated by the disclosure.

I claim:

1. A mobile scaffold comprising I a. a platform with b. a scaffolding assembly c. the said scaffolding assembly including elevating means,

I. the said elevating means having a first, second, third and fourth segment,

2. the said first and third segment, each being pivotally mounted on the said platform for elevating movement;

3. a first sheave mounted on the end of the said first segment, a second sheave mounted on the end of the said third segment,

4. the said second segment being attached to the said first sheave; the said fourth segment being attached to the said second sheave,

5. the said first sheave furnishing rotatable means between the said first and second segment. The said second sheave furnish rotatable means between the said third and fourth segments,

6. the said second and fourth segment having mechanical means to provide elevating movement, and

7. horizontal bracing extending between the said second and fourth segment,

8. the said second and fourth segments each being pivotally attached to and supporting the said scaffolding assembly,

(I. a first actuating means for raising the said first and third segments, simultaneously;

e. a second actuating means for raising the said second and fourth segments simultaneously.

2. The mobile scaffold as claimed in claim I where the said first actuating means for raising the said first and second segments is a first screwjack and a second screwjack,

a. the said first and second screwjacks each being pivotally attached on opposite ends of single power shaft, where the said power shaft is rotated by,

b. an electric motor,

c. the said electric motor being controlled by a cable toggle switch.

3. The mobile scaffold as claimed in claim I where the said mechanical means for elevating movement of the said second elevating segment consists of a. a first set of at least two braces, a first, second, third pulley and a cable,

I. the said braces being pivotally and individually attached to the said first and second elevating segment, the said braces then joining in a common point to support the said first pulley, the said first pulley being positioned between the said first and second elevating segment; the said second pulley being mounted on the said first sheave; the said third pulley being mounted at the base of the said first elevating segment; the said cable of the said first set being assembled in such a manner so as to move the said first pulley toward the said second pulley, the said cable passing around the said first, second and third pulley to a drum attached to a winch;

b. the said mechanical means for the elevating movement of the said fourth elevating segment consists of a second set of at least two braces, a first, second and third pulley and a cable,

5 6 l. the said braces being pivotally attached to the said scaffolding assembly,

third and fourth elevating segments; the said braces b. the said second set of levelling cables extending from the joining in a common Point pp the Said first p base of the platform to a second crossbar with further exl y. 316 said 518! P y being Positioned between the tension, the said second crossbar being mounted on the Said third and fourth elevafing Segments, the second said second sheave, the said further extension of the said Pulley being mounted on the Said Second sheave h second set of levelling cables further extending to the third pulley being mounted at the base of the third framework ofthe said Scaffolding assembly.

elevaing segment; the said cablbeing assembled in 5. Tile mobile scaffold as claimed in claim 4 Where a first such a manner so as to move the said first pulley toward and a second end of the Said platform is equipped the i Second pulley the sflid cable passing around 10 a. with afirst, second, third and fourth telescoping outrigger the sald first, second and third pulley to a drum atb. the said Outriggers having tached to a winch.

c. ad ustable levelling acks attached thereto. The mobile Scaffold as claimed m clalm 3 where the sald 6. The mobile scaffold as claimed in claim 1 where a motorscafiolding assembly includes a first and second set of levelling driven singlewheel assembly is mounted to the said platform cables to move the said mobile scaffold from one location to another, a. the said first set of levelling cables extendlng from the a the said motopdriven Single wheel assembly having ad base of the said platform to a first crossbar, with a further extension, the said crossbar being mounted on the said Jusmble means for changmg the vemcal Posmon of the first sheave, the said further extension of the said first set Said single'wheel assembly of levelling cables extending to the framework of the said 

1. A mobile scaffold comprising a. a platform with b. a scaffolding assembly c. the said scaffolding assembly including elevating means,
 1. the said elevating means having a first, second, third and fourth segment,
 2. the said first and third segment, each being pivotally mounted on the said platform for elevating movement;
 3. a first sheave mounted on the end of the said first segment, a second sheave mounted on the end of the said third segment,
 4. the said second segment being attached to the said first sheave; the said fourth segment being attached to the said second sheave,
 5. the said first sheave furnishing rotatable means between the said first and second segment. The said second sheave furnish rotatable means between the said third and fourth segments,
 6. the said second and fourth segment having mechanical means to provide elevating movement, and
 7. horizontal bracing extending between the said second and fourth segmeNt,
 8. the said second and fourth segments each being pivotally attached to and supporting the said scaffolding assembly, d. a first actuating means for raising the said first and third segments, simultaneously; e. a second actuating means for raising the said second and fourth segments simultaneously.
 2. the said first and third segment, each being pivotally mounted on the said platform for elevating movement;
 2. The mobile scaffold as claimed in claim 1 where the said first actuating means for raising the said first and second segments is a first screwjack and a second screwjack, a. the said first and second screwjacks each being pivotally attached on opposite ends of single power shaft, where the said power shaft is rotated by, b. an electric motor, c. the said electric motor being controlled by a cable toggle switch.
 3. The mobile scaffold as claimed in claim 1 where the said mechanical means for elevating movement of the said second elevating segment consists of a. a first set of at least two braces, a first, second, third pulley and a cable,
 3. a first sheave mounted on the end of the said first segment, a second sheave mounted on the end of the said third segment,
 4. the said second segment being attached to the said first sheave; the said fourth segment being attached to the said second sheave,
 4. The mobile scaffold as claimed in claim 3 where the said scaffolding assembly includes a first and second set of levelling cables, a. the said first set of levelling cables extending from the base of the said platform to a first crossbar, with a further extension, the said crossbar being mounted on the said first sheave, the said further extension of the said first set of levelling cables extending to the framework of the said scaffolding assembly, b. the said second set of levelling cables extending from the base of the platform to a second crossbar with further extension, the said second crossbar being mounted on the said second sheave, the said further extension of the said second set of levelling cables further extending to the framework of the said scaffolding assembly.
 5. The mobile scaffold as claimed in claim 4 where a first and a second end of the said platform is equipped a. with a first, second, third and fourth telescoping outrigger b. the said outriggers having c. adjustable levelling jacks attached thereto.
 5. the said first sheave furnishing rotatable means between the said first and second segment. The said second sheave furnish rotatable means between the said third and fourth segments,
 6. the said second and fourth segment having mechanical means to provide elevating movement, and
 6. The mobile scaffold as claimed in claim 1 where a motor-driven single-wheel assembly is mounted to the said platform to move the said mobile scaffold from one location to another, a. the said motor-driven single-wheel assembly having adjustable means for changing the vertical position of the said single-wheel assembly.
 7. horizontal bracing extending between the said second and fourth segmeNt,
 8. the said second and fourth segments each being pivotally attached to and supporting the said scaffolding assembly, d. a first actuating means for raising the said first and third segments, simultaneously; e. a second actuating means for raising the said second and fourth segments simultaneously. 